1. Field of the Invention
This invention relates in general to an apparatus for facilitating the movement of a printing sleeve with respect to a printing cylinder. More particularly, the invention relates to an improved apparatus for quickly and easily removing a printing sleeve from a cylinder and for quickly and easily installing a printing sleeve on a cylinder.
2. Discussion of the Related Art
In a printing press utilizing rotating printing cylinders, the printing cylinders are placed over shafts. The cylinders vary in outside diameter but have an inside diameter corresponding to the diameter of the shaft. Typically the cylinders are from one to three inches thick. A printing sleeve is mounted on the cylinder by sliding the printing sleeve over the cylinder, and a printing plate is mounted on the printing sleeve. The cylinder and sleeve are connected to a printing press. The printing medium is run past the rotating cylinder such that an image is transferred to the medium. After the press run is complete, the sleeve is removed from the cylinder with the printing plate still attached. The sleeve and plate combination can then be stored and reused the next time the same job is run, saving plate mounting time. To avoid having sleeves slip around the cylinder while printing, the sleeve must fit tightly. This tight fit makes the sleeve difficult to slide on and off the cylinder.
Therefore, it is desirable to have an apparatus for easily and quickly removing the printing sleeve from the cylinder. In the past, to facilitate movement of the sleeve, numerous holes were drilled on the end of the face of the cylinder. Air would be forced into the cylinder and through these holes, creating a cushion of air on the surface of the cylinder. This air cushion would slightly expand the sleeve, which is made from a composite polymeric material, and lubricates the interface between the sleeve and the cylinder so that the sleeve could be easily slid over the cylinder. However, due to the large number of cylinders used in a printing facility, the cost of drilling holes in each cylinder is extremely high.